A $9 oversized plug works as a patch, but it's not the same as fixing it right, and that's the part people skip over. Your buddy saved you money, but the threads in that pan are still chewed up, so the next shop that pulls that plug may not get it to seal again. Jiffy Lube quoting a full pan isn't crazy on its own, the pan and gasket and labor add up, where they went wrong was stripping it and then handing you the bill. I'd take it back over to your buddy in St. Paul and have him look at the threads before the Duluth trip, because a slow leak on the highway is a lot worse than a wasted Saturday.